Performance analysis of cooperative nonorthogonal multiple access with improved time switching simultaneous wireless information and power transfer protocol

This article studies a new non-orthogonal multiple access (NOMA) assisted decode-and-forward cooperative relay (NOMA-DFCR) system, where the downlink NOMA principle is employed to communicate between a source-destination pair through a dedicated relay. Performance of the proposed system is analyzed in terms of the outage probability (OP), system throughput (ST), and ergodic sum rate with channel estimation errors (CEEs) and imperfect successive interference cancellation (SIC). An approximate expression of the OP and the diversity order of the presented scheme are derived. To gain further insights, asymptotic analysis of the OP is carried out at high signal-to-noise ratio (SNR) regime. Further, we also investigate the impact of power allocation coefficients and CEEs on the system performance. Moreover, the OP of orthogonal multiple access (OMA) assisted cooperative relay system is evaluated and compared with the proposed scheme. To validate the correctness of the derived analytical results, Monte Carlo simulations are performed. Numerical and simulation results have shown that the proposed system outperforms its OMA counterpart and the schemes in References 14 and 15, in terms of both the ST and OP.

“…Please refer to Appendix B. ▪ Now, substituting (18) and ( 19) into (17), we can get the expression for P out,1…”

Section: 11mentioning

confidence: 99%

mentioning

confidence: 99%

Performance analysis of non‐orthogonal multiple access assisted cooperative relay system with channel estimation errors and imperfect successive interference cancellation

Singh

Bansal

2021

“…On the other hand, in relay‐aided cooperative NOMA network, dedicated nodes are employed as relays to improve the reliability of the far users 10,11 . In addition to this, cooperative NOMA technique can extend the network coverage and provide enhanced system throughput as well 9‐13 …”

Section: Introductionmentioning

confidence: 99%

“…10,11 In addition to this, cooperative NOMA technique can extend the network coverage and provide enhanced system throughput as well. [9][10][11][12][13] Cognitive radio (CR) concept was introduced to enhance the SE by allowing the secondary users (SUs) to access the licensed spectrum band occupied by primary users (PUs) in an opportunistic or collaborative manner, while protecting the QoS of the PUs. 14,15 Three distinct spectrum access methods were introduced for realizing the CR technology, that is, interweave, overlay, and underlay.…”

Section: Introductionmentioning

confidence: 99%

Optimal power allocation for non‐orthogonal multiple access enabled full‐duplex underlay cognitive relay networks under partial relay selection

Aswathi

Babu

2022

This article considers non-orthogonal multiple access (NOMA) enabled full-duplex (FD) underlay cognitive relay networks (ie, NOMA-FDCRNs) with partial relay selection scheme. The secondary network, where NOMA is used, consists of a secondary base station (SBS) sending messages to two secondary users (SUs), that is, a near SU (SU1) and a far SU (SU2), by utilizing a dedicated relay selected from a set of FD decode-and-forward nodes. We obtain analytical expressions for the outage probabilities (OPs) of the SUs and then deduce the asymptotic OP expressions as well. Further, expressions are obtained for the optimal power allocation (OPA) coefficients at the SBS and at the relay that separately maximizes the throughput of the secondary network in NOMA-FDCRN.Furthermore, the jointly optimal power allocation (JOPA) coefficients that maximize the throughput are also determined. The analyses consider (i) imperfect successive interference cancelation conditions, (ii) the tolerable interference limit of the primary receiver, (iii) the secondary nodes' maximum transmit power values, (iv) interference generated by the primary transmitter, and (v) the residual self-interference (RSI) at the FD relay. It is shown that the proposed OPA coefficients at the SBS and the JOPA can mitigate the impact of RSI and significantly improve the OP and throughput performance. The numerical results show that the proposed JOPA approach provides 32% and 106% improvement of throughput compared to random power allocation (RPA) and equal power allocation (EPA) strategies, respectively. The OP of SU1 and SU2 reduce by 68% and 73%, respectively, under the proposed JOPA compared to RPA, while compared to EPA, the OP of SU1 and SU2 reduce by 96% and 97%, respectively.

“…The information sent over wireless medium are exposed to various channel realizations described by various statistical models. In References 39‐41, the authors provided the performance results for dual‐hop cooperative NOMA over Rayleigh and Weibull channels, respectively. Moreover, outage probability and ergodic capacity performance of the SWIPT‐enabled cooperative NOMA system were studied in Reference 42, where the channel was modeled as Nakagami‐ m fading.…”

Section: Introductionmentioning

confidence: 99%

Performance limits of wireless powered cooperative NOMA over generalized fading

Nauryzbayev

Omarov

Arzykulov

et al. 2021

The non‐orthogonal multiple access (NOMA) technique is a prospective solution to support the massive connectivity of an ever‐increasing number of wirelessly connected devices and address the spectrum scarcity issue. In this article, the outage probability and ergodic capacity of a two‐hop cooperative NOMA network with an energy‐limited relaying node are quantified over a generalized α−κ−μ statistical model. The relay acts in an amplify‐and‐forward mode and performs energy harvesting (EH) using the time‐switching and power splitting relaying protocols. Moreover, the impact of hardware impairments (HIs) is incorporated into the performance evaluation. The obtained results prove the importance of HIs and allow one to evaluate the outage probability and ergodic capacity over various statistical models and system parameters. Finally, the results suggest that the optimal performance at a specific scenario depends on the combination of multiple factors, such as channel conditions, HI level, transmit power, and EH protocol.